This diagnostic trouble code (DTC) is a generic OBD-II powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may vary depending on the make and model. Owners of

Problems with Powertrain Control Module, also known as PCM

Failure of wastegate solenoid

Some wiring issues with the turbocharger

Issues with turbocharger bypass valve and actuator

Issues such as cracks or disconnected vacuum line

Corroded or disconnected electrical connectors

Boost controller failure

Replace/Repair These Parts To Fix OBD Code P0033

Firstly, we suggest you to get a certified technician to verify the code with a scanner after resetting the fault codes and performing a road test.

Next, what you will need to do is to perform a pressure test on the intakes system between the turbocharger/supercharger and intake throttle valve.

In case the pressure is low, you will need to check for cracks or damage in the intake hoses, intercooler, pipes and clamps. If you find them to be in best condition then check the bypass valve to determine if it is open  allowing boost pressure to escape.

In case the pressure is high, we recommend you to check the bypass valve to make sure that it opens under the maximum boost pressure 

In case you find that the pressure is in the normal range, then pressure sensor is faulty and needs to be replaced.

The other turbo boost pressure control valve design utilizes an electronic valve. The valve receives a voltage signal from the PCM (or boost controller) when applicable. The voltage signal causes the valve to open and close proportionally as required to maintain optimum boost pressure. Professional technicians report that the boost control valve is often condemned in error, when the boost pressure sensor is the defective part Using a digital volt/ohmmeter, test system circuit voltage and continuity to ensure that it is within manufacturer’s specifications. A system wiring diagram or manufacturer’s service manual (with diagnostic flow charts) will be required Disconnect system components and controllers prior to testing circuit continuity to prevent damage

Remember that the bypass valve is operated differently depending on the manufacturers. Some are spring operated especially the Asian models.